Conventionally, the image-forming apparatus of the electrophotographic system is generally provided with a developing device which has a plurality of developing members containing predetermined developers, placed face to face with an image-bearing body, and developer supplying containers installed in toner supplying sections corresponding to the respective developing members so as to supply developers to the respective developing members, and which visualizes an electrostatic latent image formed on the image-bearing body.
With respect to misinsertion preventing mechanisms used at the time of loading a toner cartridge to the toner supplying section of such a developing device as a developer supplying container, for example, Japanese Laid-Open Patent Application No. 1682/1992 (Tokukaihei 4-1682, published Jan. 7, 1992) has proposed such a mechanism. In this mechanism, a bar code reader, attached to the toner supplying section as an information reading means, reads bar code information placed on the toner cartridge, and based upon the results of the reading operation, a judgment is made as to whether or not the toner cartridge to be inserted is a suitable one; thus, based upon the results of the judgment, a misinsertion preventing shutter is operated so as to prevent misinsertion of the toner cartridge.
Moreover, there is another well-known method in which, when a developer supplying container having an information storage medium such as an non-volatile memory is inserted to the toner supplying section of a developing device, an electric circuit is formed between the developing member and the developer supplying container. In this method, information possessed by the developer supplying container is applied to the developing member side or the apparatus main body side, and based upon the results of the judgment, misinsertion is prevented.
However, when the misinsertion preventing mechanism of the toner cartridge disclosed in the above-mentioned Japanese Laid-Open Patent Publication No. 1682/1992 (Tokukaihei 4-1682) is adopted, a bar code needs to be placed on each toner cartridge and an information reading means such as a bar code reader needs to be attached to each toner supplying section, resulting in an increase in costs.
Moreover, since the bar code placed on the toner cartridge is located in the vicinity of developers and toners, it tends to be contaminated, and the optical information reading means such as a bar code reader is also susceptible to developer and toner contamination, thereby causing problems such as errors in reading the bar code.
Similarly, in the above-mentioned method in which the electric circuit is formed between the developing member and the developer supplying container provided with an information storage medium such as a non-volatile memory so as to transmit and receive the information possessed by the developer supplying container by means of electric signals, the contacts tend to be contaminated by toners and developers closely located, resulting in problems such as malcontact and abrasion.